Article

Three-dimensional coronary MR angiography performed with subject-specific cardiac acquisition windows and motion-adapted respiratory gating.

British Heart Foundation-Cardiac MRI Unit, Rm. 170, D Fl., Jubilee Building, Leeds General Infirmary, Great George Street, Leeds LS1 3EX, United Kingdom.
American Journal of Roentgenology (impact factor: 2.78). 03/2003; 180(2):505-12. pp.505-12
Source: PubMed

ABSTRACT In coronary MR angiography, data are conventionally accepted in only short and fixed periods of the cardiac and respiratory cycles. We hypothesized that a more flexible and subject-specific approach to cardiac and respiratory gating may shorten scanning times while maintaining image quality.
We implemented an acquisition technique that uses subject-specific acquisition windows in the cardiac cycle and a motion-adapted gating window for respiratory navigator gating. Cardiac acquisition windows and trigger delays were determined individually from a coronary motion scan. Motion-adapted gating used a 2-mm acceptance window for the central 35% of k-space and a 6-mm window for the outer 65% of k-space. In 10 subjects, three-dimensional coronary MR angiograms of the right and left coronary systems were acquired with this technique (the "adaptive technique") as well as a conventional acquisition method, and the scanning times and image quality were compared. The adaptive technique was then applied prospectively to 40 patients who underwent coronary radiographic angiography.
Scanning times with the adaptive technique were reduced by a factor of 2.3 for the right coronary artery and by a factor of 2.2 for the left coronary artery system compared with the conventional technique, mainly because we were able to use longer subject-specific acquisition windows in patients with low heart rates. Subjective and objective measurements of image quality showed no significant differences between the two techniques. Prospective evaluation of MR angiograms yielded a sensitivity and specificity of 74.3% and 88.2%, respectively, to detect significant coronary artery stenoses.
Coronary MR angiography with subject-specific acquisition windows and motion-adapted respiratory gating reduces scanning times while maintaining image quality and provides high diagnostic accuracy for the detection of coronary artery stenosis.

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Keywords

10 subjects
 
2-mm acceptance window
 
6-mm window
 
acquisition technique
 
adaptive technique
 
adaptive technique"
 
conventional technique
 
coronary artery stenosis
 
coronary motion scan
 
Coronary MR angiography
 
coronary systems
 
diagnostic accuracy
 
left coronary artery system
 
motion-adapted gating window
 
motion-adapted respiratory gating
 
objective measurements
 
Prospective evaluation
 
respiratory cycles
 
subject-specific acquisition windows
 
two techniques